Natural Gender Selection: the legend that won’t die

One of the enduring fertility myths is that you can increase your chance of having a boy or a girl if you time sex just right. This is loosely based on scientific data. Your baby’s sex is determined by which sperm penetrates the egg: an X (female chromosome) or a Y (male chromosome). Studies have shown that Y-bearing sperm do swim a bit faster, but have a shorter life span after ejaculation. In theory, if you had sex at the time of ovulation, it would increase the chance of having a boy because the Y sperm would reach the egg the fastest, and if you had sex several days before ovulation you’d boost the chance for a female, because the female sperm will have outlived the males. However, when put to the test, these methods have failed. Other recommendations regarding your sexual position, men wearing boxers versus briefs, and timing of sex to your vaginal pH have all been scientifically tested and disproven.

Excerpt from Perfect Hormone Balance for Fertility

2 thoughts on “Natural Gender Selection: the legend that won’t die

  1. Dear Dr. Greene,
    I just read your book on perfect balance for fertility. It was very good. Can you confirm whether or not you have an office in Pleasanton? That is listed on the www but it is not clear whether or not you still have a practice there. I would be interested in learning more.

    I have been TTC and I have been on Clomid for over 6 months and noticed more hair loss than usual. Is this a normal outcome of Clomid, and will the hair grow back?

    1. Dear Hy,
      Thank you for your kind comment regarding my book. I am so glad that you found it to be useful. Writing is truly a lonely process–compared to providing care directly to patients–so I truly appreciate the feedback.

      I can reassure you that hair loss is not a common side effect of Clomid therapy. Ironically, a drop in your estrogen levels can cause this to happend. In fact, many pregnant women experience dramatic hair loss after they deliver their baby as a result of the drop in their estrogen levels. Of course, there are other possible causes as well. I would be more than happy to try to investigate this with you if you do choose to set up a consultation.

      I no longer have an office Pleasanton, California. I now work for California IVF Fertility Center ( Depending upon where you live however, that may only create a minor inconvenience for you since we have offices in Sacramento and Davis, CA. In fact, throughout the summer, we are only seeing patients in the Davis, CA office as we remodel the Sacramento office. Thank you for your interest and feel free to call if you’d like to set up a consultation (Ph. 530.771.0177)

      Best thoughts,

      Robert Greene, MD, FACOG

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